1. Field of the Invention
This invention relates to a punctum plug adapted to be utilized in the treatment of a human eye having a deficiency of tears and more specifically relates to a punctum plug or implant having an elongated member including a central axis and having at one end thereof a distal section, which in the preferred embodiment is in the form of a collapsible expanded section, terminating in a distal tip which extends in a direction substantially normal or perpendicular to the central axis. At the other end thereof is a thin elongated retaining lip positioned to have the elongated tip extend in a generally anterior direction to extend over the punctum open and engage the lip margin of an eye upon insertion of the punctum plug or implant through a punctum opening. The elongated member including the distal section and collapsible expanded section are dimensioned to pass through the punctum opening of an eye.
This invention also relates to a method for treating external eye conditions due to a deficiency of tears utilizing the punctum plug or implant having at one end thereof a distal section, preferably in the form of a collapsible flared section, terminating in a distal tip which extends in a direction substantially normal to the central axis.
2. Description of the Prior Art
It is known in the art that certain eye problems are related to the volume of tears on the surface of the eyes. Certain of these problems include dry eyes, corneal ulcer, conjunctivitis, blepharitis, contact lens problems and many other external eye diseases.
One method for treating a deficiency of tears is disclosed in U.S. Pat. No. 4,660,546, and the invention thereof is wherein the inventor thereof is the same inventor of the present invention. U.S. Pat. No. 4,660,546 discloses a method for treating external human eye conditions due to a deficiency of tears which includes the step of temporarily blockading the canaliculus of the patient and observing over a preselected period of time the response of the patient's eye to the temporary blockage and to determine if any improvement in the eye condition has been achieved in response to the occlusion.
If an improvement in eye condition is noted, an implant is placed within the canaliculus of the eye of the patient. A temporary blockading of the canaliculus is performed by placing a dissolvable, removable element, which may be in the form of a collagen material or other dissolvable material such as, for example, catgut, in the canaliculus. Unless removed shortly after insertion, the dissolvable implant is absorbed by the body in approximately a two week period.
A determination is first made if the canaliculus blockage results in an improvement in the eye condition or other conditions caused by related nasal congestion warranting permanent blockage of the canaliculus, for example, the patient will respond to a partial 60% to 80% retention of constant tears.
If permanent blockage of the canaliculus is warranted, U.S. Pat. No. 4,660,546 discloses that the permanent blocking of the canaliculus is performed by utilizing a permanent implant. U.S. Pat. No. 4,660,546 discloses that the permanent implant is fabricated of a nonabsorbable or non-dissolvable material and is in the form of a cylindrically shaped central body having a tapered end or an end of reduced diameter to facilitate the implantation of the implant into and for removal of the implant from the canaliculus. Both the temporary collagen implant or other dissolvable material and the permanent implant disclosed in U.S. Pat. No. 4,660,546 are in the form of a cylindrically shaped central member having a predetermined diameter which may terminate at one end in a tapered end and which reduces in diameter as it slopes away from the central member to form a tapered tip to facilitate insertion of the implant through the punctum, and into the canaliculus. U.S. Pat. Nos. 4,660,546 and 5,049,146 discloses implants or lacrimal occluders which occlude the canaliculus.
U.S. Pat. No. 4,461,295, wherein the inventor thereof is the same as the inventor of the present invention, discloses another treatment method which is a method for laser punctal occlusion. It is known in the art that punctal occlusion has been proven to be an effective way of treating patients with conditions such as sinusitis, hay fever, middle eye infection (chronic), post nasal drip, front headache and other such conditions.
The treatment method disclosed by U.S. Pat. No. 4,461,295 includes the use of a temporary suture to stitch the tear drainage canals of the eyes closed to determine if a greater tear volume on the surface of the eyes would improve certain eye problems. This diagnostic procedure has become known in the art as the Herrick Stitch Test. The Herrick Stitch Test is performed by anesthetizing the local area around the lower or upper punctum of the eye. A stitch is carefully placed to occlude the punctum by an eye surgeon utilizing magnification of the eye.
After a preselected period of time using the Herrick Stitch Test, the eye surgeon determines if the eye condition has improved, if so, then the eye surgeon permanently closes the punctum by using an ARGON laser. The punctum may be reopened at a later time if excess tearing is experienced. The reopening of the punctum can be performed by surgical and laser techniques, all as disclosed in U.S. Pat. No. 4,461,295.
It is also known in the art to utilize other plugs and or techniques for occluding the punctum. One plug device which is known in the art is referred to as a punctum plug which is described in an article by Jerre M. Freeman, MD, entitled "The Punctum Plug: Evaluation of a New Treatment for the Dry Eye" which appeared in the publication of the transcripts of the America Academy of Ophthalmology and Optometry, pages OP-874 through OP-879 (hereinafter referred to as the "Freeman Reference"). In addition, the same punctum plug is disclosed and described in U.S. Pat. No. 3,949,750.
The punctum plug disclosed in the Freeman Reference and in U.S. Pat. No. 3,949,750 is a plug which is adapted to be inserted into the upper and/or lower punctal openings of the eye to block or occlude the punctum. The punctum plug of Freeman is a rod-like plug formed with an oversized rigid or solid tip or barb portion that dilates and blockingly projects into the that portion of the canaliculus located adjacent the punctum opening.
The punctum plug has a smaller neck or waist portion around which the punctum sphincter ring or fibrous tissue defining the punctum opening tightens. The punctum plug has relatively large, smooth head portion which rests on top of the punctal opening and prevents the plug from passing down into the canaliculus. The smooth head portion is designed to be domed shaped to permit the head to rest in the lacrimal lake and against the conjunctiva and cornea with little irritation. The head portion functions to prevent the punctum plug from passing or migrating further into the canaliculus. The punctum plug of Freeman is subject to being inadvertently removed from the eye by the patient.
It is also known in the art to provide for a temporary closure of the punctum by heat using a light cautery around and in the punctal opening. The punctal closure procedure is disclosed in an article entitled "Diagnosis and Treatment of Keratoconjunctivitis Sicca" which appeared in a symposium on medical and surgical diseases of the cornea, transactions of the New Orleans Academy of Ophthalmology in 1980 at page 43 wherein the authors thereof were Jose I. Barraquer, MD and eight other authors (hereinafter referred to as the "Barraquer Reference").
The Barraquer Reference further discloses that other treatment methods of temporarily closing the punctum include use of gelatin plugs, cyanoacrylate adhesives and diathermy. The use of intracanalicular gelatin implants for treatment of eye conditions is described in an article entitled "INTRA-CANALICULER GELATIN IMPLANTS IN THE TREATMENT OF KERATO-CONJUNCTIVITIS SICCA" by Wallace S. Foulds which appeared in the Brit J. Ophthal (1961) in Volume 45 at pages 625 through 627, inclusive, (the "Foulds Reference"). The Foulds Reference discloses that occlusion of the lacrimal puncta can be performed by use of and insertion of a fine, water soluble gelatin rod into the punctal openings. The gelatin rod is formed from pure powdered gelatin to which a small quantity of distilled water has been added and is heated in a water bath until the gelatin dissolves and a thick gel results. By dipping a cold glass rod into the so prepared gelatin, and withdrawing the same, fine solid rods of gelatin were formed.
The so formed gelatin rods were then inserted into the canaliculus to provide a temporary blockage. As such, the gelatin rod implants, although very fragile, provide an alternate known means for temporarily blocking the canaliculus. If an improvement in eye condition is obtained, then permanent closure of the canaliculus may be warranted.
It is known in the art that a Schirmer's Tear Secretion Test can be utilized to measure gross tear secretion. If the results of the Schirmer Tear Secretion Test discloses that an insufficient portion of the tear secretion is retained on the eyes, a temporary or permanent occlusion of the canaliculus may prove helpful to improving the above described external eye conditions.
An improvement over the Freeman punctum plug, as described in U.S. Pat. No. 3,949,750, is shown in U.S. Pat. 4,915,684. U.S. Pat. No. 4,915,684 discloses a lacrimal fluid modulating device composed of a generally cylindrical body portion with an enlarged cap at one inlet and a tapered peripheral enlargement at an outlet end. The tapered peripheral enlargement is solid. An axial bore extends completely through the modulating device and is fashioned with an outlet end having an internal diameter which is preferably no less than 0.12 and no greater than 0.36 mm.
A tapered shaft punctum plug for occlusion of the punctum opening having a tapered shaft and including one end that terminates in a narrow neck and a concave dome and another end that terminates in a solid pointed nose is offered for sale by Eagle Vision under the trademark SUPER PLUG.
Another punctum plug that is commercially available for occluding the punctum opening is known as an UMBRELLA PLUG. The UMBRELLA PLUG has an elongated cylindrically shaped central member having one end that is cut at an angle relative to the central axis and terminates in a flat, circular washer like cap or collarette. The UMBRELLA PLUG has at its other end a collapsible umbrella shaped bulb which collapses like the closing of an umbrella during insertion of the umbrella shaped bulb through the punctum and when the umbrella has passed through the punctum opening, it then reverts back to an open position.
U.S. Pat. No. 5,417,651 discloses a punctum plug and probe for lacrimal pathology which includes a plug having a flange, a neck and a foot portion or bulb portion. The flange is inclined at an angle of approximately 130.degree. with respect to the symmetry axis. The foot portion is radially flexible from its resting position towards the symmetry axis. The punctum plug constitutes a head for a metallic mandrel which functions as a probe. The probe follows the path of the lacrimal duct and can be deflected to draw it out of the nasal cavity. The structure of the punctum plug is similar to the UMBRELLA PLUG described above.
U.S. Pat. No. 5,318,513 discloses a fixation stent and a method for using the stent to repair canalicular lacerations and to block fluid flow through a canalicular canal. The stent, adapted to be inserted into a punctum of an eyelid, includes a flexible tube portion having a proximal end, a distal end, an inflatable portion in fluid contact communication with the distal end, and a plug for sealing and anchoring the proximal end with a body canal. The plug includes a T-top portion with a diameter greater than the diameter of he punctum that rests at two specific locations on the margin of the eyelid, thereby anchoring the proximal end of the stent at the margin of the eyelid.
As is evidenced by the above described prior art, the two approaches used to occlude the lacrimal drainage system are to: (a) occlude the punctum opening and that portion of the canaliculus adjacent the punctum opening, e.g., Freeman U.S. Pat. No. 3,949,750, U.S. Pat. No. 4,915,684 the SUPER PUNCTUM PLUG, the UMBRELLA PLUG and the head plug to support a mandrel as shown in U.S. Pat. No. 5,417,651; and (b) occlude the canaliculus at a location other than adjacent the punctum opening, e.g., U.S. Pat. Nos. 4,660,546 and 5,049,142. However, other implants which can be used to occlude the canaliculus both adjacent the punctum opening and at other locations in the canaliculus are U.S. Pat. Nos. 5,163,959 and 5,171,270 wherein the inventor thereof is the same inventor as in the present Application.
The use of a punctum plug as a head for a metallic mandrel which functions as a probe, e.g. U.S. Pat. No. 5,417,651 and for an anchor for a stent to repair canalicular lacerations and to block fluid flow through a canalicular canal, e.g. U.S. Pat. No. 5,318,513, basically are punctum plugs known in the art as described above.
U.S. Pat. No. 4,959,048 discloses a reversible, flexible, lacrimal duct occluder which is formed of a shaft having a low profile cap at one end and a rounded tip at the other end. The shaft has at least one, and preferably 1-3, conical ranges forward on the shaft between the ends. The rounded tip enters the punctum followed by the leading edge of the range(s) until the occluder bends at an acute angle relative to the axis of the shaft and enters the horizontal canalicular canal.
In practice, however, it has developed that the transition from that portion of the canaliculus adjacent the punctum opening, sometimes referred to as the vertical portion of this canaliculus, does not occur as a distinct transition point, but rather occurs through an intermediary section referred to as the ampula or sac which is anatomically an extension of that portion of the canaliculus that extends horizontally to the nasal sac.
Therefore, an implant which occludes the punctum opening and that portion of the canaliculus adjacent the punctum opening, depending on its length, can have a portion thereof located in the ampula or sac. By occluding the lacrimal drainage system in this manner, it is not necessary that the implant physically be located in that portion of the canaliculus which is beyond the ampula or sac to be effective.
On the other hand, if an implant, without a dome or collarette, is inserted into the punctum opening or the vertical section of the canaliculus, that implant generally migrates through the punctum opening through the portion of the canaliculus adjacent to the punctum opening, into the ampula or sac, and can easily migrate into that portion of the canaliculus beyond the ampula or sac.